iOS 9.3 is coming in the Spring and will introduce Night Shift as well as a number of other new features.
Apple: Jobs Will Not Present at Apple's Final Macworld Keynote
Apple is reaching more people in more ways than ever before, so like many companies, trade shows have become a very minor part of how Apple reaches its customers. The increasing popularity of Apples Retail Stores, which more than 3.5 million people visit every week, and the Apple.com website enable Apple to directly reach more than a hundred million customers around the world in innovative new ways.Apple's decision comes on the heels of news that Adobe would not be exhibiting at Macworld San Francisco. Several other vendors, including Belkin, Seagate, and Google, have also withdrawn from the expo or downsized their presence.